Every Garden Counts

The watershed approach to landscaping will maintains precious rainwater.

By Anne Weinberger

Published: May 15, 2017

This Oakland hills creekbed captures and retains rainwater.

Garden Design and Photo: Anne Weinberger, Garden Design

After five years of drought in California, residents have finally gotten the drenching of their dreams—and then some. The hillsides are emerald green. Neighborhood creeks have carved out dramatic waterfalls. Gardens have sprung back to life.

But Californians have also watched helplessly as torrents of precious rainwater raced down the streets, roads became riddled with potholes, and homes succumbed to mudslides. In much less than a decade, the state has now set records for both drought and rainfall.

Many Bay Area gardeners are perplexed. For years now, they’ve responded to the drought by proudly cutting back on landscape irrigation, often letting their gardens go brown. But is brown really the new green? And what can they do to save some of the water that’s being lost down storm drains?

According to a broad range of landscape-industry professionals, local agencies, and even some politicians, the answers lie in the “watershed approach” to landscaping. By treating individual gardens as microcosms of the greater ecosystem, this approach to garden design, installation, and maintenance makes the best use of the rainwater that falls in any given year.

“Homeowners are eager for creative ways to conserve water,” said landscape contractor Guillermo Yanes of San Leandro’s AY Sustainable Landscape Design, “so we teach them about allowing water to percolate into the soil to encourage deep rooting of trees and plants.” Yanes achieves this permeability in the garden using a variety of solutions. “We plant ground covers between stepping stones, use gravel for paths and patios, and contour the soil into rain gardens with plants that like wet feet in the winter,” he said.

According to Kelly Schoonmaker, program manager at StopWaste, an Alameda County agency with educational resources for sustainable gardening, the practice of building healthy soil is essential to the watershed approach. “Taking care of the soil is a critical step to gardening success and maximizing environmental benefits,” said Schoonmaker, who noted that using compost increases plants’ uptake of nutrients, suppresses disease, and sequesters carbon, while applying 3 inches to 4 inches of mulch reduces water use by 40 to 70 percent and reduces runoff by 70 to 80 percent.

Dry creekbed in Orinda stores water for nearby trees and looks beautiful year round with colorful plantings.

Selecting climate-appropriate plants spaced properly for their ultimate size and according to their needs for sun or shade is another tenet of the watershed approach. At most East Bay nurseries, gardeners can find labels and signage indicating low water use and native plants.

“After the wettest year ever, this will be the summer of decision for our customers,” said Chris Dundon, water use efficiency supervisor for the Contra Costa Water District. “Homeowners with weedy yards are deciding what to do, and we want them to make informed decisions,” he said.

Customers have been taking advantage of the district’s rebates for converting lawns to water-wise gardens, but Dundon pointed out that more than 50 percent of his customers’ water use is still going into landscape irrigation. “We’re educating our customers about the concept of seeing their property as a watershed, directing the rainwater from the gutters into a place in the landscape where it soaks into the soil so that trees and shrubs will pull from it the following summer.” The district reinforces this concept with workshops and a public Facebook group—Maintaining Your Water-Wise Landscape—with over 750 members.

Watershed-based landscape practices are also on the agenda at the state level, where state Sen. Scott Wiener, D-San Francisco, recently introduced Senate Bill 780 (Designing More Sustainable and Water-Efficient Landscaping and Lawns). In recent years, the state has been working to define guidelines for California landscapes that can be used on a voluntary basis in any garden. The legislation is in committee hearings.

“Watershed-wise landscaping is a way to successfully make gardens that are not just pretty on the outside, but workhorses on the inside,” said Maureen Decombe, sustainability chair for the California chapter of the Association of Professional Landscape Designers. “While nurturing beautiful habitats for pollinators and birds, these gardens also quietly maximize the benefits of our rainwater and clean our air, making us all a part of the solution to climate change and weather extremes.”

The Four Elements of Watershed-Based Landscape Practices

A watershed approach treats individual homes and their gardens as miniwatersheds within the greater watersheds that surround them. From the roof to the low point of the garden—that’s a watershed. The more impermeable the surfaces, the more water will run off, carrying with it the pollutants and sediment that eventually reach the bay.

The benefits are many, including improving soil biology; reducing, or eliminating the need for fertilizer, and improving plant health and disease resistance; reducing runoff, greatly cutting irrigation requirements as plants tap into water stored in soil; capturing pollutants; pulling carbon from the air and locking it up in the soil, reducing greenhouse gas; cooling the soil; reducing weed growth; and attracting wildlife.

Watershed: A watershed is the area of land where all of the water that falls on it and drains off of it goes to a common outlet.

Resources

Want to learn how to transform your patch of ground into a watershed-wise garden? These organizations can help.

StopWaste.org, an Alameda County public agency offering techniques for sustainable gardening.

Watershed Wise Professional Landscape Training, an EPA-Watersense-approved program of G3 or Green Gardens Group, presenters of a Watershed Approach to Landscapes class, a unique workshop educating landscape professionals and home gardeners together.

ReScape California, tools for sustainable landscaping, including Bay-Friendly Landscaping and Gardening program with training for design and maintenance professionals.

WaterSmart Gardener, a program of East Bay Municipal Utility District.

Lawn to Garden Rebate Program, a program of Contra Costa Water District.

Basins of Relations Watershed Restoration and Training, one of several workforce development programs of Urban Tilth, based in Richmond.

Friends of Five Creeks offers work parties, walks, and Bay Currents talks.